Field of the Invention
The invention relates to an access control method, and particularly relates to an access apparatus of memory card and a control method thereof.
Description of Related Art
Along with progress of technology, portable electronic devices (for example, smart phones, tablet PCs, etc.) having a variety of different functions (for example, phone call, mobile Internet accessing, multimedia data playing, etc.) can bring a lot of conveniences to people's lives, so that the portable electronic devices are widely used all over the world. The portable electronic device in the market generally has a data storage device (for example, a memory card, a hard disk, etc.) for storing data (for example, files, music, video films, etc.). Along with widespread of the portable electronic devices, the data storage devices are also widespread, and techniques thereof are continuously ameliorated and developed. The memory card (for example, a multi media card (MMC), a secure digital (SD) card, a compact flash (CF) card, etc.) is one of the most commonly used data storage devices.
On the other hand, in some specific cases (for example, to store important data, etc.); a user does not want the stored data to be duplicated or modified. In order to protect the data stored in the memory card, memory cards having a write-protection switch are developed. For example, FIG. 1A and FIG. 1B are examples of an SD card having a write-protection switch. Referring to FIG. 1A, the SD card 100 has a write-protection switch 105 with a sliding structure. When the write-protection switch 105 is pushed to a top position of a sliding zone thereof, and the SD card 100 is inserted into a slot of an access apparatus, a moving terminal 130 in the access apparatus is pushed by the write-protection switch 105 and is electrically connected to a detection terminal 135, such that a pin connected to the moving terminal 130 outputs a low level voltage, and now the SD card 100 is in a read/write state. Referring to FIG. 1B, when the write-protection switch 105 is pushed to a bottom position of the sliding zone thereof, the moving terminal 130 is not electrically connected to the detection terminal 135, such that the pin connected to the moving terminal 130 outputs a high level voltage, and now the SD card 100 is in a read-only state.
However, in the aforementioned write-protection mechanism implemented by sliding the write-protection switch, if the write-protection switch is slid too frequently, the write-protection switch is probably loosened or even falls off, which results in a fact that the SD card is only identified to be in the read-only state and causes inconvenience to the user. Moreover, during a process of manufacturing the SD card, an upper and a lower protection cases of the SD card usually cannot be completely packaged in one packaging process, such that the gap of the write-protection structure becomes a potential reason for splitting the protection cases. Therefore, it is necessary to provide a more stable and reliable method to implement the write-protection mechanism of the memory card.